As pearly luster particles which are excellent in high-temperature stability, Patent Publication 1 describes a mildly cold pearly luster concentrate containing a pearly luster coloring agent which consists essentially of a fatty acid base material selected from the group consisting of hydroxyl stearate, polyethylene glycol mono- and di-stearates, ethylene glycol mono- and di-stearates, stearic acid monoethanolamide, and mixtures thereof, wherein at least about 90% by weight of the fatty acids of the above fatty acid base material is composed of octadecanoic acid. However, in order to obtain the pearly luster coloring agent, it is necessary to use a high-purity octadecanoic acid purified from fatty acid raw materials. Therefore, the cost involved in manufacturing increases.
Patent Publication 1: JP2001-514627 A